xj running like crap...

I'm not sure what it can be I have an 88 laredo when i start it up it runs fine but when it starts warming up to normal temp it spudders when I give it gas. If you guys can help me out id appreciate it

Start here:

http://www.naxja.org/forum/showthread.php?t=1012701

O2 sensor is ignored at start up, and the ECU computer starts to use O2 sensor data once the O2 sensor warms up.

All you need is a multi meter, volts and ohms tests.

Also test the CPS, the CTS and the IAT sensors, and grounds. The 87-90 years are known for bad sensor grounds. Search and read up on the C-101 bulk head connector problems, signal degradation (87 and 88 years only)....Read the new sticky above on Cruisers Renix TPS fixes (Renix is 87-90 year XJs)

The CTS and IAT are temperature sensors, Coolant and Air Intake. If they go bad they manifest as temp sensitive running issues.

Lastly, slight chance it might be a sticking or leaking EGR valve.

Does it sputter cold when you give it gas? If yes, go directly to testing the TPS, Throttle Position sensor.

Also read the "RenX files"

http://www.naxja.org/forum/showthread.php?t=905849

No it isles and runs fine when its cold buy thank you for all the info

Then do the O2 sensor tests first. Easy test, is disconnect the O2 sensor, and see if the problem goes away. If it does, then do the O2 sensor harness tests for the ground, and the 12 volts going to the O2 sensor heater, before replacing the O2 sensor. It could be wiring on the O2 sensor or the really that feeds 12 volts to the O2 sensor heater that is bad, or the O2 sensor itself.

Ok thanks man